What is Coenzyme Q10?
Coenzyme Q10 (CoQ10) is an important compound found in every cell in the body. It is a type of coenzyme, which means that it helps enzymes work more effectively. CoQ10 is mainly located in the membrane of mitochondria, where it is used to make energy .
CoQ10 helps shuttle electrons in the mitochondria to produce ATP, the main form of cellular energy .
Energy-demanding organs in your body have the highest levels of CoQ10. These include the brain, heart, kidneys, muscle, and liver – all of which contain many mitochondria and use a lot of energy .
Many different diseases and conditions, as well as nutrient deficiencies, can reduce the body’s ability to make CoQ10 or cause CoQ10 to be used up faster than it can be replaced. In these cases, supplementation may be helpful or necessary .
CoQ10 is commonly supplemented to help improve diseases that involve mitochondrial dysfunction and increased oxidative stress such as fibromyalgia, chronic fatigue syndrome, and diabetes. Supplementation may also be beneficial for heart diseases, including heart failure .
Some people also take CoQ10 supplements to combat the side effects of statins. Athletes, on the other hand, use them to enhance performance .
- Beef chicken, and pork (highest levels in the heart and liver)
- Fish (herring and sardines, highest levels in the heart) and seafood (shrimp and scallops)
- Nuts (highest in sesame seeds)
- Legumes (highest in peanuts)
- Vegetables (highest in parsley and soybeans)
Ubiquinone vs. Ubiquinol
CoQ10 is mainly found in two forms in the body: ubiquinone and ubiquinol. Ubiquinone is the oxidized version in the body that is recycled (reduced) back into ubiquinol and vice versa. Ubiquinol is primarily responsible for the antioxidant benefits of CoQ10, although ubiquinone may have some antioxidant potential [8, 9].
Ubiquinol makes about 90% – 98% of the CoQ10 in the blood, while ubiquinone makes only a small percentage. Both forms are carried around the body by LDL and HDL. The ratio of ubiquinol to ubiquinone decreases as you age due to poor conversion between the two forms and increased oxidative stress [10, 11, 12, 13].
- Increases energy levels
- Protects cells and blood vessels from free radicals
- Improves heart health
- Reduces blood sugar levels
- Reduces migraines
- Improves fertility
- Protects against side effects caused by statin drugs
- Poorly absorbed without fat or oil
- Possible interactions, especially with blood-thinning drugs (warfarin)
Commercial tests usually measure CoQ10 levels in the blood. However, CoQ10 can also be measured in muscle cells, immune cells, and saliva.
Blood levels may not always accurately reflect the amount of CoQ10 in your tissues and cells. You can have normal or even high levels in the blood but still show a deficiency in your muscles and immune cells [14+, 15+].
The normal range for blood CoQ10 levels varies between labs but is usually between 0.4 – 1.9 mg/L (or μg/mL) .
The ratio of ubiquinone to total CoQ10 (%CoQ-10) is also used as a marker of oxidative stress, with higher numbers indicating higher levels of oxidative stress. People with liver disease or liver cancer often have high %CoQ-10 levels .
Overall, men tend to have higher CoQ10 levels than women .
Total levels slowly rise through pregnancy, normally increasing by as much as 67%. Lower levels (< 0.50 mg/L) are linked to spontaneous abortions .
Low Coenzyme Q10 Levels
Causes and Associated Conditions
Sepsis is a serious condition in which the body mounts an excessively strong immune response to an infection in the bloodstream. The condition increases the demand for CoQ10 and causes abnormally low levels .
Cancer reduces the body’s ability to make CoQ10. One study found that 22% of breast cancer patients had CoQ10 levels below 0.5 mg/L compared to only 4% of women without cancer. Low CoQ10 levels are also found in myeloma (cancer of white blood cells), colon, skin, and kidney cancers [20, 21+, 22].
HIV and AIDS patients are often low in CoQ10, with the risk of deficiency increasing the more severe the disease .
An overactive thyroid (hyperthyroidism) results in very low CoQ10 levels. Hyperthyroidism increases the rate of energy production, which causes the body to use more CoQ10 than normal. Hyperthyroidism also reduces the number of lipoproteins that carry CoQ10, meaning less CoQ10 is available to be measured [24, 5].
Diabetes is marked by high oxidative stress and mitochondrial dysfunction. CoQ10 blood levels may fall in people with type 2 diabetes. In one study, type 2 diabetics had 45% lower CoQ10 levels than healthy people [25, 26, 27, 28, 29+].
In type 1 diabetics, CoQ10 levels are slightly elevated or normal. However, research in type 1 diabetics is limited to children and young adults, who are better able to adapt to the increased oxidative stress and maintain normal CoQ10 levels [25, 26, 27, 28, 29+].
7) Genetic Mutations
Phenylketonuria (PKU) is a disorder caused by a mutation in the PAH gene that results in low levels of tyrosine (an amino acid used to make CoQ10). About 33% of PKU patients have low CoQ10 levels .
Mucopolysaccharidoses (MPS) are a group of genetic diseases caused by mutations in genes responsible for the breakdown of glycosaminoglycans – long chains of sugar found in bones, skin, and connective tissue. People with MPS often have low CoQ10 levels because they are deficient in vitamin B6 .
8) Low Testosterone Levels
11) Vitamin Deficiencies
Vitamins B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (folic acid), and B12 (cobalamin) and vitamin C are all needed to make CoQ10. A deficiency in any of these vitamins may lead to low CoQ10 levels [43+].
Toxic compounds in cigarette smoke increase free radicals, which causes the body to use up CoQ10 to neutralize them. Smoking reduces CoQ10 levels much more in women than men .
In a study of 81 people, those with asthma had 35% lower CoQ10 levels .
A study of 1.5k children and adolescents with migraines found that 33% had levels below the reference range of 0.5 mg/L .
15) Chronic Fatigue Syndrome
CoQ10 levels are much lower in people with chronic fatigue syndrome (CFS) than healthy people. Low levels may play a role in the extreme fatigue CFS patients experience and are also directly linked to worse symptoms. Levels below 0.39 mg/L were associated with more pronounced concentration and memory problems in a study of 70 people [47, 48, 47].
In a study of 57 healthy and depressed people, only those with depression had low CoQ10 levels. Of them, those with both treatment-resistant depression and chronic fatigue syndrome had the lowest levels .
Schizophrenia is a severe mental disorder that involves mitochondrial dysfunction and increased oxidative stress. People with schizophrenia have been found to have low levels of CoQ10 in their blood cells [49, 50].
18) Prader-Willi Syndrome
Prader-Willi syndrome (PWS) is a genetic disorder that causes muscle weakness and poor growth, symptoms that mimic those seen in people with low CoQ10 levels.
In a study of 44 people, those with PWS had 50% lower CoQ10 levels than those without the disorder .
A slight deficiency in CoQ10 results in fatigue and muscle weakness .
Severe deficiencies are mainly caused by genetic mutations and show up early in life. Severe deficiency results in :
- Damage to the part of the brain responsible for muscle coordination and balance (cerebellum)
- Kidney damage
- Muscle fiber damage
- Stunted growth
- Rash, severe arthritis, and brain inflammation in infants (infantile multisystemic disease)
- Loss of mental and movement abilities (Leigh syndrome)
- Death (if the deficiency is not corrected)
Conditions Associated With High Coenzyme Q10 Levels in the Blood
People with fibromyalgia have higher than normal CoQ10 levels in their blood, possibly due to CoQ10 not being able to enter tissues and cells. However, their immune cells have lower than normal CoQ10 levels [53, 14+].
Health Effects of Low Coenzyme Q10 Levels
1) Mitochondrial Dysfunction and Oxidative Stress
Because CoQ10 plays a key role in mitochondrial function and antioxidant protection, a deficiency may lead to mitochondrial dysfunction and increased oxidative stress.
2) Muscle Loss Due to Aging (Sarcopenia)
As we age, we lose muscle mass and function due to a number of factors, a process known as sarcopenia. Low levels of the reduced form of CoQ10 (ubiquinol) is linked to an increased risk of sarcopenia .
3) Increased Risk of Skin Cancer Spreading
In skin cancer (melanoma) patients, levels below 0.6 mg/L increased the risk of the cancer spreading 8-fold .
4) Increased Risk of Breast Cancer
Lower CoQ10 levels are associated with an increased risk of breast cancer in both pre- and postmenopausal women. In one study of 993 women, levels below 0.44 mg/L had nearly twice the risk of developing breast cancer [56, 57, 58].
5) Increased Risk of Death From Heart Failure
Heart failure occurs when the heart is unable to pump enough blood to meet the body’s needs. Lower levels of CoQ10 are linked to an increased risk of dying from chronic heart failure .
Health Benefits of Coenzyme Q10 (Ubiquinone)
The following benefits are based on studies that involved supplementation with ubiquinone (the oxidized form of CoQ10). You can learn more about ubiquinol, including its health benefits and dosage, here.
1) Improves Heart Health
CoQ10 protects the heart from high cholesterol levels in mice. It also prevents damage to heart cells, improves recovery, and reduces oxidative stress and inflammation after a heart attack in rats [60, 61, 62].
Hypertrophic cardiomyopathy is a type of heart disease in which the walls of the heart become abnormally thick, causing an irregular heartbeat and making it harder for your heart to pump blood. Taking 200 mg/day CoQ10 for improved heart function, irregular heartbeat, and quality of life and reduced the heart wall thickness in 87 people with HCM. In another study of 7 HCM patients, 200 mg/day CoQ10 was able to reduce heart wall thickness by 26% [63, 64].
Heart failure involves increased levels of oxidative stress in the heart and increases the requirement for antioxidants like CoQ10. CoQ10 levels in the heart are lower in people with more severe heart failure .
In a 2-year study of 420 people with heart failure, taking 300 mg/day CoQ10 reduced the number of deaths due to the disease by 43%. A 1-year study found that CoQ10 reduced the number of people who required hospitalization for worsening heart failure. Supplementation also reduced the incidence of fluid buildup in the lungs and asthma [66, 67].
A review of 14 studies and 2.1K heart failure patients found that CoQ10 reduced the risk of dying by 31% but did not improve heart function or symptoms of heart failure .
In people who previously experienced a heart attack, 1 year of supplementing with 120 mg/day reduced occurrence of new heart attacks and deaths due to heart disease .
CoQ10 given within 3 days of a heart attack reduced heart pain, irregular heartbeat, and improved heart function in 144 people. The number of new heart attacks as well as deaths was also reduced in the group taking CoQ10 .
CoQ10 improves heart health and is especially beneficial for thickening of the heart and heart failure. It also benefits people who have experienced heart attacks and it particularly protective if given within days of experiencing one.
Heart Surgery Outcomes
A review of 8 studies found that CoQ10 taken before heart surgery reduced the need for drugs after surgery and the development of irregular heartbeat .
One study found that taking CoQ10 for 14 days before heart surgery helped maintain heart CoQ10 levels, improved heart function, and reduced recovery time .
Blood Vessel Health and Circulation
Nitric oxide (NO) is a molecule that helps improve circulation by causing blood vessels to dilate. Healthy blood vessels produce NO to allow proper blood flow and prevent narrowing of the arteries. Free radicals such as superoxide inactivate NO, which prevents blood vessels from dilating and decreases circulation. CoQ10 neutralizes superoxide and increases nitric oxide levels [75, 76, 77, 76, 78].
In multiple studies of over 135 people, CoQ10 (100 – 300 mg/day) improved blood vessel health and increased circulation. CoQ10 supplementation increased levels of superoxide dismutase, an enzyme that neutralizes superoxide [79, 80, 78, 68].
In a rat model of a heart attack, CoQ10 protected blood vessels from damage due to lack of blood flow .
Multiple studies of over 280 total people with high blood pressure have found that supplementing with CoQ10 (100 – 225 mg/day) reduces blood pressure. Reductions in systolic pressure ranged from 8% to 11% and diastolic pressure ranged from 9% to 12% [82+, 83+, 84, 85+].
However, two 12-week studies (40 people with slightly high blood pressure and 30 people with high blood pressure) found no effect from supplementation with 200 mg/day. Another study of 55 people with slightly high blood pressure found no change after 4 months of taking either 600 mg or 1,200 mg daily [80+, 88, 89].
There is good research to suggest CoQ10 reduces blood pressure in people with high blood pressure. People with normal or slightly high levels may see little or no effect.
High Blood Pressure in Pregnancy
Preeclampsia is high blood pressure during pregnancy, with swelling in the hands and feet. Women who took 200 mg/day CoQ10 20 weeks before delivery had a 20% reduced risk of developing preeclampsia (197 total women) Another study of 197 women found a 44% reduced risk of developing preeclampsia [90, 91].
Supplementing with 100 mg CoQ10 daily for 20 days reduced the size of platelets and helped prevent them from sticking together .
In one study, CoQ10 reduced oxidative stress associated with rheumatoid arthritis .
The membrane that surrounds cells contains fats that help keep it stable. These fats can become oxidized and damaged, which causes the cell to not work as well. CoQ10 is found within the cell membrane where it acts to prevent this oxidative damage .
CoQ10 is carried around the bloodstream by lipoproteins such as LDL and HDL. LDL is especially prone to becoming oxidized, when it becomes more dangerous than regular LDL and may trigger plaque formation and hardening of the arteries. CoQ10 helps prevent LDL from becoming oxidized [95+, 96, 3].
A review of 9 studies and 428 people found that CoQ10 reduced TNF-α, but had no effect on CRP or IL-6 .
However, another review of 17 studies and 811 people found that CoQ10 reduced CRP, IL-6, and TNF-α [102+].
CoQ10 may reduce inflammation by reducing the production of NF-κB. NF-κB is a protein that controls genes responsible for producing inflammatory compounds [102+].
4) Reduces Blood Sugar Levels
A meta-analysis of 18 studies and over 700 people found that CoQ10 reduced blood sugar in those with high and normal levels with doses below 200 mg/day and in studies no longer than 12 weeks [103+].
One study found no effect on blood sugar in 60 diabetics who supplemented with 120 mg/day for 12 weeks. However, insulin levels decreased. In 23 diabetics, 200 mg/day for 6 months had no effect on blood sugar or insulin sensitivity. In another 8-week study of 80 people with prediabetes, the same dose improved insulin sensitivity without affecting blood sugar levels [105, 106, 107].
In mice with diabetes, CoQ10 reduces blood sugar levels by reducing oxidative stress in insulin-producing cells (beta cells) and increasing antioxidant levels such as superoxide dismutase and glutathione. In cell studies, CoQ10 prevents programmed cell death (apoptosis) in beta cells [108, 109, 110, 111].
In lower doses (200 mg/day or less), CoQ10 may reduce blood sugar levels in people with normal and high levels by reducing insulin levels, improving insulin resistance, and protecting beta cells.
5) Reduces Diabetes Complications
High blood sugar levels in diabetes damage the nerves, causing pain, tingling, and numbness (diabetic neuropathy). In 24 diabetics suffering from neuropathy, 400 mg/day CoQ10 improved nerve function and symptoms of nerve damage .
CoQ10 prevented nerve pain and reduced inflammation in diabetic mice .
In diabetic mice, CoQ10 prevented nerve pain due to abnormally low blood sugar levels .
In animals, CoQ10 also protected the brain, kidneys, and heart from diabetes-related damage.
For example, diabetes can cause brain dysfunction and altered levels of neurotransmitters such as serotonin. CoQ10 reduced oxidative stress and balanced neurotransmitter levels in the brains of diabetic rats [111, 111].
6) Improves Fertility
Male fertility is determined by the number (count) and quality (motility and morphology) of the sperm. Sperm cells rely on CoQ10 for the energy needed to move and for its antioxidant protection .
A study of 22 men found that taking 60 mg/day for 103 days improved in vitro fertilization rates .
A 26-week study of 212 men with infertility found that 300 mg/day of CoQ10 improved sperm count and motility. A slight increase in testosterone was also found .
Supplementing with 400 mg/day for 6 months improved motility in 22 men with infertility [123+].
200 mg/day for 12 weeks reduced oxidative stress in 47 infertile men but had no effect sperm count or quality .
Poor ovarian reserve (POR) is a term used to describe a reduction in quantity and quality of immature eggs in women of reproductive age. It can reduce the success of in vitro fertilization (IVF). CoQ10 increased the IVF rate and the number of high-quality embryos in women with this condition, as well as pregnancy and live birth rates .
In aging mice, CoQ10 improves the number and health of immature eggs .
In a cell study, CoQ10 added to sperm samples improved sperm motility .
In higher doses (> 200 mg/day), CoQ10 may boost fertility in men by protecting sperm from damage and providing the energy needed for proper motility. More studies need to confirm CoQ10’s effects on fertility in women as well as its ability to increases testosterone levels in both infertile and healthy men.
7) Reduces Migraines
In multiple studies, CoQ10 (100 – 300 mg/day) reduced the duration, frequency, and severity of migraines. In one study, 150 mg/day reduced the number of migraines by over 50% after 3 months [127, 128, 90, 46].
8) Helps with Fibromyalgia
Fibromyalgia is characterized by altered CoQ10 distribution in the body and increased oxidative stress. CoQ10 levels may be high in the blood, but low in immune cells. Supplementation can increase CoQ10 levels in immune cells, which protects them and lowers oxidative stress .
In multiple studies, CoQ10 supplementation (100 – 300 mg/day) improved symptoms of fatigue, pain, headache, and depression. Supplementation also reduced inflammation and improved mitochondrial function [53, 129, 94, 130+, 131, 132].
One study in 18 people with depression found that 400 – 800 mg/day CoQ10 for 4 weeks reduced the severity of the depression and improved symptoms of sadness, fatigue, and difficulty concentrating .
Another 8-week study of 69 people with bipolar depression found that taking 200 mg/day CoQ10 improved symptoms of depression including fatigue and difficulty concentrating [137+].
10) Protects the Brain
In Parkinson’s disease, dopamine neurons get destroyed. Dopamine is important for movement, learning, and feelings of reward. CoQ10 levels are lower in the mitochondria of people with early Parkinson’s disease [138, 139, 140].
In a mouse model of Parkinson’s disease, CoQ10 protected neurons dopamine-related neurons .
A trial of 80 people with early Parkinson’s disease found that taking either 300 mg, 600 mg, or 1,200 mg daily for 16 months slowed the decline in mental and physical function. The greatest benefit was seen in the group taking 1,200 mg .
But in a small trial of 17 people with Parkinson’s, 3,000 mg Coq10 daily for 2 months did not improve mental or physical function compared to placebo .
Higher doses (> 1,200 mg) of CoQ10 for longer periods may help people with Parkinson’s disease, but this is still uncertain.
Huntington’s disease is a genetic disorder that causes physical and mental problems early in life. Mitochondria in the brains of people with Huntington’s become damaged and don’t work as well they should. CoQ10 improved mitochondrial function and health in the brains of Huntington’s disease patients .
A study of 347 people with Huntington’s disease found that taking 600 mg/day for 2.5 years slightly improved mental function and ability to handle day-to-day tasks. However, the results did not reach significance .
In rats with Huntington’s, CoQ10 improved survival, slowed physical worsening, and prevented loss of neurons .
Friedreich’s Ataxia and Familial Cerebellar Ataxia
Friedreich’s ataxia and familial cerebellar ataxia (FCA) are hereditary diseases that result in problems with muscle coordination, movement, speech, and balance. A study of 97 people found that those with Friedreich’s ataxia had 33% lower CoQ10 levels .
In a 2-year study of 50 people with Friedreich’s ataxia, CoQ10 (600 mg/day) and vitamin E (2,100 IU/day) improved walking ability, coordination, and speech. A 4-year study of 10 people with Friedreich’s ataxia found that 400 mg/day Coq10 in combination with vitamin E (2,100 IU) improved walking ability and slowed the progression of the disease in 7 people [149+, 148+].
People with familial cerebellar ataxia (FCA) have low levels of CoQ10 in their muscles, which may be related to symptoms of weakness and trouble coordinating movements. Six case reports of people with FCA found that doses between 300 mg/day and 3,000 mg/day for one year improved strength and well-being and muscle coordination, and reduced seizure frequency [150, 151+].
Alzheimer’s disease is characterized by beta-amyloid plaques and tau proteins in the brain. In mice with Alzheimer’s disease, CoQ10 reduces oxidative stress, beta-amyloid plaques, and tau proteins in the brain. However, a clinical trial in 78 patients with Alzheimer’s disease found that ubiquinol did not improve markers of disease activity or oxidative stress [152, 153, 154, 155].
Coq10 protected the brains of rats exposed to the insecticide DDVP and improved their brain function by improving the health of their mitochondria .
11) May Delay Muscle Wasting
Muscular dystrophies are a group of genetic disorders that cause muscle wasting, weakness, difficulty breathing, and poor balance. CoQ10 improves physical ability and greatly increases lifespan in mice with muscular dystrophy. In two studies of 27 people with muscular dystrophies, 100 mg CoQ10 daily improved their ability to walk and exercise and reduced their fatigue .
12) Mitochondrial Diseases
Mitochondrial diseases are a group of disorders caused by mitochondria that don’t function correctly. CoQ10 improves symptoms of mitochondrial disorders including poor nerve function, muscular weakness, tremor, inability to exercise, cramps, and muscle stiffness [160, 161, 162, 163, 164].
13) Multiple Sclerosis
14) Chemotherapy Side Effects
A review of 6 studies found that CoQ10 protected against damage to the heart and liver during chemotherapy .
In a 5-year study of 81 people who had melanoma surgery, those who took CoQ10 (400 mg/day) in addition to the anti-cancer drug were 13 times less likely to have the cancer spread compared to anti-cancer drugs alone. The CoQ10 group also had better mood and energy levels .
15) Side Effects of Statin Drugs
Statins block the production of CoQ10 and decrease its levels. One of the most common side effects of statins is damage to the muscles, causing weakness and pain (in 10 – 15% of people). These side effects may be due to low CoQ10 levels and often cause people to quit taking statins [175, 176, 177].
In a study of 50 people taking statins, 100 mg/day CoQ10 reduced muscle pain and improved their ability to accomplish daily activities .
In 20 athletes taking statins, 200 mg/day improved muscle strength .
Statins can also interfere with the ability of the heart to pump blood. CoQ10 supplementation is able to reverse this and improve heart function in people taking statins .
16) Reduces Gum Inflammation
CoQ10 reduced gum inflammation in 30 people with gum disease .
When applied directly to the gums, CoQ10 improved gum health and reduced bleeding .
17) Helps With Dry Mouth
Dry mouth is thought to be caused in part by reduced ATP saliva production. Supplementing with CoQ10 increased saliva production in a study of 66 people with dry mouth [187+].
18) Improves Lung Diseases
People with chronic obstructive pulmonary disease (COPD) have difficulty breathing and lower CoQ10 levels than healthy people. In an 8-week study, CoQ10 increased oxygen in the blood, decreased heart rate during exercise, and improved exercise performance in 21 people with COPD .
In 41 people with bronchial asthma, a combination of CoQ10, vitamin E, and vitamin C reduced the dosage of drugs (corticosteroids) needed .
19) Protects the Skin
UV radiation from the sun causes free radical damage in the skin, leading to wrinkles. CoQ10 applied to skin decreases free radicals and inflammation and increases antioxidant levels. It also reduces the depth of wrinkles and decreases oxidative stress and DNA damage due to UV radiation [190, 191, 192, 193].
20) May Slow Aging
A trial of 443 elderly people, selenium (200 mcg) and CoQ10 (200 mg/day) over a 4-year period improved vitality, physical performance, and quality of life .
There’s not enough evidence to say if CoQ10 can increase lifespan, although scientists are investigating the possibility. CoQ10 increases the lifespan of rats, bees, and worms. On the other hand, mice deficient in CoQ10 live shorter lives. However, other studies in mice and rats have found no effect on lifespan [197, 198, 197, 199].
21) Liver Health
Nonalcoholic fatty liver disease (NAFLD) is a liver disorder that involves chronic inflammation. Taking 100 mg decreased liver enzymes (AST and GGT) and markers of inflammation in a 12-week study of 41 people with this disorder .
22) Improves Peyronie’s Disease
Peyronie’s disease (PD) is a disease in which scar tissue builds up in the penis causing curvature, erectile dysfunction, and painful intercourse. In a clinical trial of 186 people with this disease, 300 mg/day CoQ10 reduced scar tissue, the curvature of the penis, and improved erectile function .
Benefits with Limited Evidence
The following studies were conducted only on animals and/or cells.
23) Gut Health
In rats, CoQ10 prevented damage to the gut from alcohol .
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen can cause damage to the gut. CoQ10 reduced gut damage by increased antioxidant levels and boosting levels of gut-protective prostaglandin E2 [206, 207].
In a rat model of ulcerative colitis (UC), CoQ10 improved gut health by reducing oxidative stress and inflammation .
24) Bone Loss (Osteoporosis)
CoQ10 increased oxidative stress and reduced cell growth in cancer cells without affecting normal cells. CoQ10 prevented cell growth and caused programmed cell death in cervical cancer cells [213, 214].
In rats, CoQ10 reduced the growth of tumors in the colon and blocked the development of precancerous lesions .
It’s unknown if CoQ10 has anti-cancer effects in humans, clinical trials would need to determine this.
Exercise-Related Fatigue and Performance
A study of 17 people found that those taking 300 mg/day CoQ10 for 1 week were able to pedal faster during a bicycle workout and felt less tired after .
However, 150 mg daily did not increase energy output in 6 physically-active people after 4 weeks .
In another study of 18 cyclists and triathletes, 1 mg/kg (0.45 mg/lb) CoQ10 daily for 28 days had no effect on athletic performance. Additionally, in a study of seven triathletes, 100 CoQ10 with 600 mg vitamin C and 270 mg vitamin E did not affect fatigue or performance during cycling exercise [218, 219].
200 mg/day for 12 weeks did not affect exercise performance in chronic kidney disease patients either .
In 41 trained and untrained people, 200 mg CoQ10 similarly had no effect on aerobic endurance .
CoQ10 may only be effective in reducing exercise-related fatigue and increasing fatigue at higher doses (> 300 mg) and in untrained athletes. The evidence to support this benefit is very weak.
Effect on Cholesterol Levels
CoQ10 reduced total cholesterol and increased HDL cholesterol in people with heart disease, according to a review of 8 studies including over 500 people. However, it had no effect on LDL cholesterol or triglyceride levels .
According to another review of 21 studies and 1k people, CoQ10 does reduce triglyceride levels in people with metabolic disorders but has no effect on total, LDL, or HDL cholesterol levels .
In mice, CoQ10 helps remove cholesterol from arteries and transport it to the liver to be broken down and removed from the body .
CoQ10 may improve cholesterol levels in people with heart disease and triglyceride levels in people with metabolic disorders. More research is needed.
Studies in rats show that CoQ10 decreases with age. Human studies are conflicting. One study in humans found that levels in multiple organs including the heart, liver, and kidneys all peaked before the age of 20 and decreased with age .
In a study of people aged 22 – 100, levels were lowest in those aged 90 – 100 years. However, CoQ10 levels were not associated with age but instead with levels of lean mass (muscle). And another study found that CoQ10 levels were actually higher in older adults compared to younger adults. In older adults, physical activity was linked to higher CoQ10 levels while in younger adults, activity was associated with lower CoQ10 levels [228, 229].
The decline in CoQ10 with age may not be due to the aging process per se but to the loss in muscle mass and activity that occurs with aging. Tissue levels may reliably decrease with aging.
CoQ10 Side Effects & Precautions
Common Side Effects
CoQ10 is generally very well-tolerated, even at the high doses. Side effects are mild and include :
- Upset stomach
- Loss of appetite
CoQ10 is processed by the liver and is eliminated through bile. This means people with poor liver function or blocked bile ducts who supplement with CoQ10 may accumulate high levels in their body, increasing the risk of side effects .
CoQ10 increases the rate at which warfarin is removed from the body [232+].
Let your doctor know if you’re taking warfarin and plan on supplementing with CoQ10 as well.
Blood Pressure-Lowering Drugs
Blood Sugar-Lowering Drugs
Theophylline (Elixophylline, Theochron)
CoQ10 increased the time it took the drug theophylline (used to treat asthma and COPD) to reach peak blood levels in rats. People taking theophylline should consult their doctor before supplementing with CoQ10 .
P-glycoprotein is a protein that pumps foreign substances – including supplemental CoQ10 – out of cells. It is inhibited by certain drugs including digoxin (for heart failure) and quinidine (for irregular heartbeat). In a cell study, CoQ10 absorption was improved when the drugs digoxin (Digox) and quinidine (Quinidex) were added [235+].
CoQ10 Dosage & Supplement Forms
CoQ10 supplements come in two forms: ubiquinone and ubiquinol. If the supplement label only has “CoQ10” on it, then it is most likely ubiquinone.
For most of the studied diseases and conditions, 100 – 300 mg of ubiquinone divided into two daily doses is effective. Higher doses may be needed to see improvement in neurodegenerative diseases [236, 102, 94, 80, 66, 84, 149+, 151+, 142].
Taking a dosage of 1,200 mg of ubiquinone daily is safe long-term. Up to 3,000 mg daily may be safe in the short-term (up to 2 weeks). However, doses above 2,400 mg/day do not result in any further increase in blood CoQ10 levels [142, 151, 143, 237].
CoQ10 is fat-soluble, meaning it is best absorbed when taken with a meal that contains oils or fats. CoQ10 formulations that are mixed with oil are absorbed better than powders and pills. Taking vitamin C and vitamin E at the same time as CoQ10 may reduce its absorption [1, 238, 239+].
A cell study found that grapefruit juice increased the absorption of CoQ10 in gut cells .
Even when it is consumed with a fatty meal, CoQ10 is still poorly absorbed. Absorption also varies greatly between people due to differences in gut bacteria and the ability to absorb fats [221, 239+].
CoQ10 is often combined with vitamin E to enhance its antioxidant effects .
People who supplement with CoQ10 generally report increased mental and physical energy levels as well as improved strength and stamina. Fibromyalgia patients report decreased pain in addition to improved energy and mental clarity. Some users do report fatigue and brain fog when taking it.
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CoQ10 is vitally important to maintaining energy levels and preventing oxidative stress in the body. Even though we make it in our cells, we also get some from the foods we eat. The heart is the organ with the highest levels of CoQ10 in the body.
Low levels of CoQ10 can be caused by various diseases, conditions, nutrient deficiencies, and statin drugs. People with diseases that involve high amounts of inflammation and oxidative stress may benefit greatly from CoQ10 supplementation, such as those with heart disease, fibromyalgia, and diabetes.
Besides producing energy in the form of ATP and protecting cell membranes, CoQ10 reduces blood pressure, helps with migraines, protects against side effects caused by statins, and improves fertility. It may also help with neurodegenerative disorders such as Parkinson’s disease as well as mitochondrial diseases.
CoQ10 is very safe and only has mild side effects. However, it can reduce the effectiveness of the popular blood-thinning drug warfarin. Absorption of CoQ10 is poor so it should be supplemented with a meal that contains fats or oils. Up to 1,200 mg/day is safe for long-term supplementation.